1. Technical Field
The present invention relates to both a method and an apparatus for testing the functionality of printed circuit board assemblies. More specifically, the invention relates to an apparatus that can be easily configured to test a wide variety of assemblies.
2. Description of the Related Art
One of the most important issues for makers of printed circuit board assemblies is the cost of testing each assembly to ensure it functions properly. In view of the increasingly lowered cost of producing the assemblies, the cost of testing takes on greater significance. For example, it is common for the cost of testing a board""s functionality to be 30% to 40% of the cost of the product. Thus, the cost of testing is a significant percentage of the overall cost of the product.
The cost of testing the functionality of printed circuit board assemblies impacts many industries. For example, most personal computers contain several printed circuit board assemblies. A standard computer will have a motherboard, a modem board, a video board, as well as others. One option is to simply not test the boards at all. However, this results in increased customer dissatisfaction due to non-functional products. Further, the cost of warranty repair increases. In other words, not testing merely shifts increased costs downstream in the product""s life.
The problem arises with the number of different boards to be tested. Each assembly may be on a different sized board. A tester must be able to easily accommodate different sized boards. Next, the boards may have several input connections located at different positions on the board. A tester must be able to be flexible enough to mate with those inputs and be able to provide the correct standard connection. Finally, a successful tester must include the necessary test electronics to provide a routine set of inputs and detect the assembly""s output. The tester must be able to compare the detected output against a list of expected outputs to determine if the assembly is functioning within expected parameters.
This invention allows the functionality of a variety of printed circuit board assemblies to be tested. The device under test is tested in a fashion that would match its actual function in the consumer""s world. In other words, the device under test is powered up, multiple inputs provided and the outputs compared to set of expected outputs for compliance to determine if the device is passed or failed.
The apparatus includes two main elements, a test hardware enclosure and a test fixture. The test hardware enclosure, also referred to as the test enclosure, can be a commercially available enclosure that houses the test equipment. For example, the test equipment could include any mountable electronic equipment needed to run or monitor the test, such as a computer and peripherals, a digital volt meter, a digital logic analyzer, oscilloscopes, a network analyzer, a modem, a CRT, cameras, and pneumatic controls. The front panel of the enclosure is a personality board. Due to its modular nature, the personality board can also be referred to as the personality module. It is designed to interface with the device under test. The inwardly facing surface of the personality board is the system back plane, and connects the personality board to the test equipment in the housing. The outwardly facing surface of the personality board contains the several interface plugs that interconnect with the input/output leads for the device under test. The interfaces can also be referred to as the interface modules.
The test fixture is an assembly that mates with the hardware enclosure. It can be secured to the enclosure without the use of any tools. The test fixture can be altered with access modules, allowing the fixture to be quickly configured to any product. The device under test resides on a non-conductive pallet designed for that specific device under test. The pallet is placed on a drawer plate on the test fixture. Once the device under test is securely attached to the test fixture, the test fixture can engage the test enclosure. The device under test then engages the interface module on the personality board. The tester can be either manual, semi-automatic or automatic.